Orofacial cancer and its sequelae can produce disfigurement, serious problems related to food and airway management, and severe speech impairment. The intent of this project is to thoroughly describe the speech characteristics of a wide variety of orofacial cancer patients, including those with partial or total glossectomy, mandibulectomy, maxillectomy and/or more extensive facial excisions. Data obtained from analyses of acoustic, aerodynamic, biomechanical and perceptual characteristics of speech in these patients will provide the basis for attempts to model both the nature and degree of speech impairment in orofacial cancer. An additional objective is to evaluate, within each resection category, the effects on speech of variables such as pre- or post-surgical radiation, type of reconstructive procedure and post-treatment sensory-motor integrity of the oral complex. It is expected that information resulting from these studies will direct the formulation of principles useful to the prognostic and therapeutic management of speech rehabilitation in this patient population. In particular, observed effects of vocal tract alterations will be incorporated in the design of speech prostheses in selected patients. Though individual patient differences must be accounted for, it is anticipated that principles extracted from the proposed initial studies of speech will ultimately enable the computer-assisted design of speech prostheses on an "a priori" basis. That is, "input" regarding an individual's unique anatomical and physiological circumstances, related to knowledge of vocal tract parameters critical to the normalization of speech, will lead to a prosthetically modified vocal tract (computer simulated) which could be tested for speech "output" prior to the actual fabrication of a prosthesis. Evaluation of each prosthesis' effects on speech will be followed by revisions and further evaluation in order to refine and elaborate this process. A final objective, also dependent on the outcome of preliminary studies, will be and investigation of the potential for movement in certain types of glossal prostheses. Insights gained from the successful completion of some or all of the study objectives outlined here could restore communicative power to patients whose loss of speech skills is often extremely debilitating and, in fact, a serious deterrent to all aspects of rehabilitation.